since you have a surface rust issue- (minor or more severe)-if
it is not completey removed(sand blasting etc.) it will return.
That may cost the big bucks and then you can paint it any color
you wish without worry about it not lasting. Problem is is that
these items were never properly treated for long term paint
results. If there is a John Deere dealer near you they have spray
bomb(can) product named Blitz Black. They use it for chassis paint and
it dries to a wounderfull satin black finish. so just clean up the metal as best you can and paint. the stuff is forgiving in results
and can be touched up easily.